To stem the flood of traffic along York Road -- the conduit to jobs, shopping and entertainment throughout northern Baltimore County -- state and county officials have tried every planning and traffic management trick imaginable.

They have widened the road and tinkered with traffic lights. They have built new interchanges and constructed a light rail line. And they have rejected proposals for large commercial developments.

But little has changed. Like other suburban roads such as Ritchie Highway, Liberty Road, Reisterstown Road, U.S. 40 and Belair Road, York Road has become increasingly clogged and dangerous amid the inexorable crush of suburbia.

In the past decade, the number of cars on York Road between Padonia Road and the Beltway has grown from about 32,000 a day to more than 40,000 a day. The number of reported accidents increased from 122 in 1992 to 137 in 1996.

As the area develops, traffic is bound to get worse. Timonium Mall is undergoing a major renovation; Redland Genstar Inc. is developing a 60-acre parcel for two large retailers, offices and a hotel; four supermarkets and several restaurants also are expected to open. Hunt Valley, meanwhile, is evolving from a manufacturing center to an office park, with more than 3,000 jobs being added by MBNA Corp. alone in the next few years.

Mary Pierce can hardly imagine congestion getting worse. She has one word to describe York Road's traffic: "horrendous."

The Mays Chapel resident tries to avoid the stretch between Towson and Hunt Valley when she shops and runs errands. "I just kind of scoot around on the back streets."

But as one of the county's major arteries, York Road isn't easy to avoid. Like many other suburban commuters, Pierce eventually ends up on the road, where she works as a receptionist for Kissinger Financial Services.

York Road, built in the 18th century to transport grain from southern Pennsylvania to Baltimore, developed slowly. A hundred years ago, fewer than 25 buildings lined what was then a dirt turnpike, according to "A History of Baltimore County."

One of the authors, Eric G. Rockel of Timonium, recalls having no fear of crossing York Road on his way to Lutherville Elementary School in the 1960s.

But the success of Hunt Valley and the development of residential communities such as Mays Chapel and Cockeysville transformed the area. From 1980 to 1990, the population in the Timonium-Hunt Valley area grew by 24 percent, and today, one-fifth of all trips made within the county each day occur in the corridor.

Not yet failing

The State Highway Administration categorizes York Road as a class D road -- congested but not yet failing.

Public transportation, widely seen as the answer to traffic congestion, hasn't had much impact on York Road. Despite bus service and a light rail line, more than 90 percent of the area's residents travel by car, and about 90 percent of those travel alone, according to a county report.

York Road is lined by car dealerships, gas stations, restaurants, office buildings and shopping centers as well as the Maryland State Fairgrounds, which is the site of consumer and trade shows almost every weekend.

"It's not unlike any of the other commercial corridors in the area," said county Planning Director Arnold F. "Pat" Keller.

In some ways, York Road is a planning success. Commercial development is compressed into an area within close proximity to homes. The street is busy, but no intersections are failing by State Highway Administration standards. Some shopping centers are showing their age, but vacancy rates are low and the road is still main street to several well-established communities.

'It's built out'

But York Road's lines of unimpressive strip shopping centers and parking lots reflect some of the worst aspects of suburban planning and set a pattern that's difficult to change.

"It's built out," said Kathy Schlabach, a county planner. "It's not going to be terribly easy to redevelop it right now."

Yet community leaders and planners are trying to change these strips and revitalize the older communities that surround them.

One tactic has been to resist requests to change zoning along York Road from residential or manufacturing to commercial uses, which tend to generate more traffic.

Another step has been to scrutinize large projects. For example, a proposed Price Club at York and Aylesbury roads was rejected after residents protested and the county Planning Board ruled that it would generate too much traffic in the area.

Councilman Douglas B. Riley, a Towson Republican, said it is unlikely that another large commercial project will win approval on York Road. "We have to change our way of thinking."

Meanwhile, the county will soon open the Beaver Dam Road extension, which will run parallel to York Road and is designed as a thoroughfare for warehouses and industries in the area.

Keller said improving the appearance of York Road is key to its revitalization.